(a) Field of the Invention
The present invention relates to a thin film panel and a method of manufacturing the same.
(b) Description of the Related Art
A thin film panel is the most widely used panel type for flat panel displays such as liquid crystal displays (LCDs) and organic light emitting diode (OLED) displays, because of its light weight and thinness.
The thin film panel provides a plurality of pixel electrodes arranged in a matrix, and the image display of the panel is accomplished by applying individual voltages to the respective pixel electrodes. For the application of the individual voltages, a plurality of three-terminal thin film transistors (TFTs) are connected to the respective pixel electrodes. Signals are provided using a plurality of gate lines to transmit signals to control the TFTs and a plurality of data lines to transmit voltages to be applied to the pixel electrodes. The gate lines and the data lines are provided on the panel.
OLED displays are devices that display characters or images by applying an electrode current to an organic emitting diode, at which the pixel electrode is disposed. LCDs are devices that display images by applying an electric field to a liquid crystal layer disposed between two panels and thus by regulating the strength of the electric field to adjust the transmittance of light passing through the liquid crystal layer.
When the display signal lines are disconnected in the process of manufacturing the display device, the disconnection is detected via predetermined tests. Such tests include an array test, a visual inspection (VI) test, a gross test, a module test, and so on.
The array test is used to detect the disconnection of the display signal lines by applying predetermined voltages and sensing whether output voltages are generated or not, and is performed before a mother glass is divided into separate cells. The VI test is used to detect the disconnection of the display signal lines by applying predetermined voltages and then viewing the panels, and is performed after the mother glass is divided into separate cells. The gross test is used to determine the image quality and connection status of the display signal lines by applying predetermined voltages and viewing display states of a screen, and is performed before mounting driving circuits thereon. Typically, the predetermined voltages are applied after combining a lower panel and an upper panel of the flat panel display. The module test is used to determine the optimum operation of the driving circuits, and is performed after mounting the driving circuits thereon.
However, when the predetermined voltage is applied for the array test, if disconnections of signal lines such as the data lines, the gate lines, and the test lines are generated due to the manufacturing method, the array test is abnormally executed. Accordingly, the resulting array test may not be sufficiently stable and reliable. In some cases, the resistance of certain structures may be increased due to undercuts, and application of the predetermined voltage may lead to signal line disconnection due to excessive resistive heating. When the test lines disconnect during the array test due to melting or other heat-related damage, the results of the array test are unreliable.
A motivation of the present invention is to provide a thin film transistor array and a method for manufacturing the same to achieve stable and reliable array testing.